BACKGROUND: Evidence regarding all-cause and cause-specific mortality in inflammatory bowel disease (IBD) is conflicting, and debate exists over appropriate study design to examine these important outcomes. We conducted a comprehensive meta-analysis of all-cause and cause-specific mortality in both Crohn's disease (CD) and ulcerative colitis (UC), and additionally examined various effects of study design on this outcome.METHODS: A systematic search of PubMed and EMBASE was conducted to identify studies examining mortality rates relative to the general population. Pooled summary standardized mortality ratios (SMR) were calculated using random effect models.RESULTS: Overall, 35 original articles fulfilled the inclusion and exclusion criteria, reporting all-cause mortality SMRs varying from 0.44 to 7.14 for UC and 0.71 to 3.20 for CD. The all-cause mortality summary SMR for inception cohort and population cohort UC studies was 1.19 (95% confidence interval, 1.06-1.35). The all-cause mortality summary SMR for inception cohort and population cohort CD studies was 1.38 (95% confidence interval, 1.23-1.55). Mortality from colorectal cancer, pulmonary disease, and nonalcoholic liver disease was increased, whereas mortality from cardiovascular disease was decreased.CONCLUSIONS: Patients with UC and CD have higher rates of death from all causes, colorectal-cancer, pulmonary disease, and nonalcoholic liver disease.